De-humidifier question

[Syke]

We experience slight condensation problems in our 3-bedroom, centrally (oil) heated, double-glazed house. The windows are aluminium frames. We are thinking of a de-humidifier and see that Ebac are offering a 28 day trial of one of these. We are inclined to the 2650e model, which incorporates an air-purifier unit as well.

Does anyone have experince of this or similar? Would it have to be moved from room to room or would some central position be all right? Are they very noisy?

Regards and thanks in advance

Pat Macguire

[choco]

We just got Amcor 99 quid ones in a couple of flats. Makes a big difference, also the place heats up much more easily so you don't get cold areas and rooms so much. Just leave them in the one location ourselves and they seem ok. Quite noisy though. The amcor ones at least have a fast/slow speed so you could leave it on full for a week or two and then switch to slow - probably about as loud as a fairly loud pc on that setting. I think you can also get ceramic(?) ones which are lighter, quieter and about twice that price but I didn't try.

[Mark S.]

Get one asap, top device. :-)

Wouldn't goto the expense of air purification just a standard one.

Mine's a bit noisy to have on at night unless it's downstairs but stick it on in a morning when you goto work etc.

Takes a while to catch up with the "dampness" but the first time you tip 8 litres of water out of it you'll not regret it.

Mark S.

[Andrew Gabriel]

I have one. They aren't very satisfactory for this purpose because they create uneven humidity in the house. They work very well, actually too well in the area where they are located, but not elsewhere. This means things like floorboards get drier on one side than the other, and curl up, and laths might shrink away from plasterwork (may not be such a problem in a newer huose with chipboard floors). They are too heavy to move around often, and usually need to stand still for some period after being moved before being switched on (just like a fridge or freezer, although you can get away without if you avoid tipping or shaking during moving). They are too noisey to use in a quiet room, and can generate some vibration in the floor, depending on type of floor.

What you probably need to do is improve the ventilation in the house, and ensure the (central?) heating is as uniform as possible to avoid cold spots. If you have first generation aluminium double glazing with no thermal break in the aluminium frames, then you probably won't be able to avoid these forming condensation. I used to have these, but had them replaced as they had been fitted to the original timber sashboxes which had then gone rotten.

[Dave Liquorice]

Where is the condensation, just on the frames or the glass as well?

Personally I think you'd be better off improving the ventilation, particulary in the water vapour generating rooms (kitchen and bathroom). Just running a cooker hood whilst doing vapour generating activities (cooking, hand washing up) and for a while afterwards really does reduce condensation. Like wise an extractor running whilst you bath/shower and for a while afterwards will make a significant difference.

Dehumidifier just treat the symptom not the root cause and cost much more in capital, maintenance and power than a couple of extractor fans.

[Syke]

Well, the condensation, in all rooms when it's very cold, appears at the bottom of the panes,on the inch or so of white-painted aluminium there, and it's not doing the sills any good. The first solution I considered was, in fact, extractor fans, but would say, two of these, (kitchen and bathroom), really be cheaper and more flexible than a dehumidifier in terms of capital cost anyway?

Regards

Pat Macguire

[Dave Plowman (News)]

I'd be amazed if a properly heated house with lath and plaster walls suffered from condensation except perhaps in a heavily used bathroom or kitchen? Unless someone has been blocking off all the designed ventilation

- and I don't mean fitting double glazing.

[Dave Liquorice]

Extractors come in at around =A330 each but take a few tens of watts for= the time they are on more or less fit and forget. A dehumidfier takes a few hundred watts and generally speaking will need to be on for much longer periods and need more looking after, emptying the container, cleaning the filters etc.

[Dave Liquorice]

We do but since changing the cooker hood from recirculate to extract the problem downstrairs is much reduced. Upstairs is still a problem on a landing window and one bedroom next to the bathroom that has no ventilation. One of the many round tuits is to fit an extractor to the bathroom...

[Fred]

Extractors come in at around £30 each but take a few tens of watts for the time they are on more or less fit and forget. A dehumidfier takes a few hundred watts and generally speaking will need to be on for much longer periods and need more looking after, emptying the container, cleaning the filters etc.

I have measured mine to take 200 watts. I think the posters here are generally correct. You should get rid of the problem rather that treating the symptoms. Ideally a house should be ventilated to change its air every few hours. perhaps someone here can post the building reg figures or even those used when sizing radiators.

[Harry Bloomfield]

Syke submitted this idea :

Rather than trying to extract the moisture with a de-humidifier, it would be better to ensure surplus moisture is taken out at source with extract fans. If you don't have one already, fit a bathroom extractor fan and use it. Fit a cooker hood which vents to the outside.

Doing the above makes a very noticeable difference to the amount of moisture in the air, but if your aluminium frames are of the uninsulated type then some moisture can still be expected to condense on them in colder weather.

[Dave Liquorice]

Overall I think it's around 1 change per hour.

I had a quick google but got a rather in consistent range of answers... Domestic kitchens seem to be about 10 changes/hour, bathrooms a bit less at 8.

[N. Thornton]

Fwom:Syke ( [e-mail])

centrally (oil)

yep

no, yep

no theyre quiet, but not silent. Think PC. Suggest locating unit in kitchen or bathroom, not in bedroom.

Air purifier waste of time.

Be sure to get a humidistatic one, makes no sense to buy cheaper non-stat ones.

Second hand ones are £15 to £60.

no, purchase and fit for 2 fans costs more. Dehumidifiers you just plug in.

right, but dont overlook the facts that a) the fans chuck hundreds of watts worth of heat outside apiece when they run, the dehumidifier doesnt. b) fans arent free to fit c) fans are usually noisier d) and in my experience not particularly effective unless run for long periods, chucking large amounts of heat out.

And since one can fit a secondary lock to a window to enable it to be locked half an inch ajar, fans are a doubly dud option.

not found that myself, quite the opposite.

just pouring the gallon container into the sink once every 2-3 weeks. Dont get one with a filter.

Depends, not always. If the excess damp results from frequent shower use, you cant really elmiinate that at source, and a dehumidifier is generally the best option.

NT

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[Dorothy Bradbury]

I wouldn't go the dehumidifier route, but if you do...

Dessicant rotor based -- silica gel impregnated rotor o Rotor turns by a motor, simple fan to blow air over it

---- rotor surface moves thro a heated chamber to dry out dessicant

---- water collected in a container o Amber Dry & Amber Ruby are 2 colours of the product (B&Q £189) o Work very effectively below 5oC, let alone 20oC o Running 500W (note, as they are partly room heaters)

Compressor based -- phase-change system o Less efficient as temperature drops below 20oC, poor below 10oC o B&Q £75 to a couple of hundred, cheap ones lose motor bearings in

[Mike]

You give information on life of the compressor type. Any views on these ? We tried a compressor one and took it back as it was useless at the temperature we keep the house.

Is Amber the brand name ?

[Andrew Gabriel]

I've got 3 identical ones which came from Homebase about 5 years ago (it was closing down, they were going dirt cheap and I couldn't resist;-).

400W, no name on them. I use one in an airing cupboard -- it will dry a washing machine load of cloths in about an hour (longer for bath towels and heavy jeans). The condensate gets used in the steam iron, and the excess for watering the plants. The other two are with other members of the family. One was plumbed in and ran continuously (subject to its humidistat) for many months in a damp house, which is how I know what damage they can do to a house, but the unit itself had no problems. One developed a fault on the PCB which prevents the compressor restarting within 2 minutes of shutting off, which I fixed. The compressors themselves have had no problems -- I would expect them to last for many years like fridge and aircon ones do. One failure mode for these devices I have heard of is some part of the condensate collection corrodes through, and they start leaking condensate on the floor. Hasn't happened to any of mine yet though. I would suspect the fan motor would have a shorter life than the compressor, if I was to guess what else might fail.

[Dorothy Bradbury]

I'm not sure if Amber is the brand name: o Do a Google for Amber Ruby - they are ~£259 there

---- for a rotor-dessicant dehumidifier that's OTT

---- costs should in theory be far less than for a compressor type

---- the ruby one is white & blue o Then check

re B&Q who do another Amber unit

---- the price is £189-199 delivered and it is an identical model

---- the other Amber unit is a charcoal colour

When you do the Google you'll see a comparison: o Compressor type v rotor-dessicator type over temperature o Compressor type = output falls sharply down to ~5oC operation o Rotor-dessicator type = output is a flat line to ~5oC & works even lower

If used in a small volume environment, a compressor dehumidifier will increase the air temperature markedly so boosting the dehumidification efficiency into the "ideal temp zone" yet costing from £75 vs £189. So for drying clothes in a confined space compressor types have economics.

Rotor dessicators are standard in industry: o Work very well at lower temps - eg, drying unheated areas o Draw little power - fan motor, rotor motor, heater to dry rotor segment out o Exhaust the moist air - 1 duct in, 1 duct out, 1 duct to outside environment o Very quiet indeed - just a fan & rotor-motor

The Amber units do not exhaust to the outside, but drive off the water and then somehow condense it (Peltier?) which uses more energy (ie, 500W v 210W).

Compressors are rarely a failure mode - so little longevity gain there. Both compressor & rotor-dessicator type use fans - and that comes down to bearing quality. I've lost two WDH-101 cheap compressor units to motor bearings, the bearings are replaceable - but the local tip has a recycler there so he got a pre xmas present to make some money on them.

Can not recall who makes the Amber unit, the markup is silly that I do know, and at least B&Q are undercutting the others by £50 on price. Looks like the generic dehumidifiers are now doing a compressor-less model - one at £150. However the same proviso applies re bearing quality if run 24/7 for years.

The benefit of compressor-less is potential to be really quiet re bedroom use, they are priced to "early adopters" right now as costs I'm sure are quite low. If you don't need the heating, you are paying for ~500W additionally.

[bof]

In message , Dave Liquorice writes

One of mine too, well in the kitchen at least, one thing I hate about them though is the racket they make, anyone recommend a quiet one? if such a thing exists I'm sure I'll get the tuit too.

[Mike]

Thanks - most helpful. Do you think prices will come down soon ? I can hold off until next autumn.

[Mike]

Just bought one of these - unfortuneatly actually £199 in B&Q - and am amazed by the performance. Rooms that ordinary de-humidifiers wouldn't touch have yielded litres of water in a few hours. I'm not impressed often but for one I am.